Reddit reviews How to Rebuild GM LS-Series Engines

There are dozens (hundreds?) of guides for the LS engines. Books, YouTube, forums, etc. all offer potential advice and walk-throughs for the actual rebuild process. If you can't find any you like, try: https://www.amazon.com/How-Rebuild-GM-LS-Engines-ebook/dp/B00V8SS2EY

Far more important is what you want to build this engine for, street/strip, drag racing, hauling, 4x4, and what you want to spend for the total project. Set a budget for the entire thing because it is very easy to blow $1000s on a motor with many fancy aftermarket parts that don't actually work together well and that don't work for the vehicle it's going into. That's a great way to lose interest in the project when it doesn't perform the way you'd like, and the hobby in general.